Bearing



Patented 1.1, a, 1945 Franskllensehlnliala polk, man-user to we a P. I; Mall." l (10., 130-, litilllnlpolb, Incl, a

corporation of Delaware This invention relates to bearings.

An object of the present invention is to improve copper base" bearings.

Other objects of the-invention will be apparent from the following description taken in connection with the appended claims.

The present invention comprises the combination of elements. and the product thereof brought out and exemplified in the disclosure hereinafter set forth, the scope of the-invention being indicated in the appended claims.

While a preferred embodiment of the invention is described herein, it is contemplated that'considerable variation may be made in the method of procedure and the combination of elements without departing from the spirit of the invention.

In the prior art, bearings have been formed of copper or bronze containing various percentages of lead. While such bearings have performed with considerable satisfaction and have relatively high strength combined with low friction qualities, such bearings have not always been satisfactory in llparticulars. For example, it has been difiicult to obtain uniform distribution. of lead throughout'the copper matrix and this has resulted in some non-unifo'mity of bearing properties.

Bearings of the type described are frequently bonded to a steel backing for additional strength and support. Such bonding requires the application of relatively high temperatures for a comparatively long period of time. Such prolonged heating, however, interferes with the proper distributlon of leadand promotes the accumulation of the lead in relatively large globules. Such large size lead inclusionsare not as effective in promotingabearing ofuniformlylowfrictionas areuniformly distributed fine particles of lead.

Lead is also subject to a certain amount of oil;

corrosion when used in bearings.

- The present invention contemplates a copper "base bearing of improved characteristics. According to the present invention, the bearing is formed of a copper base metal composition containing thallium instead of lead. It is contemplated that within the following fame of proportions:

Percent Thallium arose Copper Substantially the balance The proportion of thallium used will be varied dependingupontheservieetowhichthebearing Copper--- the Application December 20, 1941, Serial No. 428,101

Claims. (01. see-m) will have the highest strength-and are especially useful where the bearing is not provided with a steelbsokingshell. Buchallmmbeproduced by first melting the copper, then adding the thaliiuin to the melt. In some cases a small proportlonofother ingredientswillalsobeusedtoimprove the properties of the alloy either during melting or during. use. In any event. the melt should be thoroughly stirred before pouring. The slloycan be used in'the formlof castings or in somecasesthecastmaterialmaybeforgedtothe the bearing may be formed of metal compositions I is requiredto be subiected. The lower'percentagesof thallium such as: I I

Ilium 010 desired form. Photomicrographs of the material show relatively small globules of thallium uniformly distributed throughout the casting at the grainboundariesofthecoppermatrix.

Bearings having this lower thallium content have sufilcient strength to withstand fairly heavy loadswithoutsteelbackingsandmay alsobesublected to impact loads when used with or without steel Another class of copper-thallium bearings comprises the group having the composition:

Per cent Thalllum 10 to 20 oe pea hnlhi. Substantially the balance sinneesrmrsaren'efejrsblrmvmedwimstea haoklngshells to which the! may be integrally attachedby fusion welding. casting, centrifugally esstinmbraflnscr-cthsrmesns. sincethese comm suneapplies'tiths percentages of thallium as;

Perce t Copper substanflallythehalanoe Mormons-mausoleum orlkbiueselmotcrsandmayor'maynot hesteei bac 'Ihebearingsofthepresent'invantime'anhe made by several manufaetm'ing as by the melting. mixing-and scribedabove. Theycanalsoha madebysimultaneously electroplating thallium from a suitable..

It'is bymi'iingthemetalpowders,

mmdlll'imins themixture'. thismethodissmtable forv the entire composition rangedisclosed it is particularly advantageous percentages ,oi' thallium are iseasier to prevent recr ation of the taking plaice. I, In casting, a of thallium segre-t gaticn may thorough mising is achievedfollowed by afairlyrapid cooling.

another methodof manufacture comprises balance so spraying mixed molten partielssof copper-and.

'a Shori gun wherein metal powders are used.

It is of advantage in some cases to improve the 5 -characteristics 01' the copper by the addition of relatively small quantities oi materials which act either as grain refiners or hardening ingredients or both. One of the most useful materials is tin which may be present in proportions varying from .1 to by weight of the composition. The tin increases the hardness and strength of the copper base and increases the resistance of the bearing to fatigue.

Instead of tin, silver may also be used to increase the strength of the copper base and it does so without greatly decreasing the thermal con-' ductivity of the bearing. Silver also appears to provide a nucleus-forming ingredient which promotes the fine and homogeneous distribution-of the free thallium phase. Nickel and manganese also act as grain refiners and improve the physical properties of the bearing. 1

Thallium and copper do not form solid solutions and hence the thallium is distributed in the bearing in the form of small particles interspersed resistance I Percent (2) Thallium 22.42

In order to still further improve the corrosion vantage with the grains of the copper matrix. These small thallium particles or soft. Moreover. cold present at a bearing surface, does not harden the thallium particles. It is believed that this is one factor which renders copper-thallium compositions so well suited for bearing purposes.

since the thallium particles will melt at-a temperature of approximately 578' 1''. they will aflord liquid lubrication if the oil supply should be temporarily heated.

The hardness or the copper-thallium alloys at room temperature and at is low. For instance, a bearing of:

Per cent 'Ihallium Copper Balance had a Brinell hardness of 36 at 80? F. and the hardness was reduced to 27 at 355 F. The bear- 7 ing was found to have excellent anti-friction 1 characteristics.

Another bearing formed of:

Per cent Thallium 10 Copper Balance was also found to have high anti-friction characteristics.

Alloys of the following compositions, when melted, thoroughly stirred and chill cast showed a uniform fine dispersion of the thallium at the rain boundariesof the copper matrix:

- Per cent (1) Thallillm 11.11'

Tin I 2.87 Copper 3.181106 globules are very ductile and working, such as is always 1 cut off and the bearings become overelevated temperatures alkaline earth metals as the finished bearing and then heat treating the bearing to difluse the indium into the surface. Indium and thallium form a series of solid solutions which are highly corrosion resistant. The indium plating can be diflused into the thallium at slightly elevated temperatures such as 300 F.

In some cases the rectly to the copper-thallium alloy prior to casting. One such bearing alloy which was found to show a very pronounced segregation of thallium globules in the grain boundaries had the-composition: r p

- Per cent 4.78 Indium .45 Copper Balance It may also be of advantage in preparing the bearing alloy to add small amounts of alkali or deoxidizers. These mealso eiiect grain refinementand may increase the" hardness of the thallium somewhat.

application is'a continuation-in-part of myco-pending application for Bearings, serial No. ssasoam d September 16. 1938.

' While the present invention, as to its objects and advantages. has been described herein as carried out in specific embodiments thereof,v it is not desired to be limited thereby but it is intended to cover the invention broadly within the spirit and scope of the appended claims.

What is claimedis:

.1. A hearing formedof a. metal composition of .2to 35% thallium'and the balance substantially all copper.

2. A hearing formed of a metal composition of s to 10% thallium and the balance substantially all copper.

3. A bearing formed of a metal composition of.

10 to 20% thallium all copper.

4. A bearing formed of a metal composition of 20 to 35% thallium and the balance substantially all copper.

- 5. A copper base bearing formed of a copper. base matrix and small particles i'pf' thallium distributed in the bearing at the grain boundaries of the copper base matrix, said 2 to 35% by weight of the bearing composition.

6. A copper base bearing formed of a copper base matrix and small particles of thallium distributed in the'bearing in the found small particles interspersed with the grains of the copper matrix, said thallium forming 2 to 35% by weight of the bearing composition,

. FRANZ R. HENSEL.

and the balance substantially Balance of the alloy it has been found of ad- I in some cases to apply a coating of in-' indium can be added di-.

thallium forming v 

